DLm8000 can hold up to 1.8 petabytes of raw capacity, expected to ship by the end of this year

The new DLm8000 Disk Library follows three earlier versions of "disk libraries" or disk archive arrays - the DLm1000, DLm2000 and DLm6000. The earlier disk libraries were built using either EMC's Data Domain virtual tape library or its midrange VNX storage array.

All four EMC disk libraries can be managed through the same management interface.

Like EMC's smaller libraries, the DLm8000 offers RAID 6 protection, so that up to two hard drives can fail without the loss of data. The array also offers deduplication and hardware-based data compression capabilities.

The DLm8000, which is expected to be available in the fourth quarter, can replicate data over IP from a source mainframe to one or two remote sites. Users can replicate part of all of their tape backup data, choosing what data has recover priority.

Besides an increase in capacity, the new DLm8000 introduces - for the first time - synchronous replication via EMC's Symmetrix Remote Data Facility (SRDF). Data can be replicated over distance continuously to a secondary data center or disaster recovery site.

"Data consistency becomes key, especially for customers that measure the cost of downtime with each transaction in tens of thousands of dollars," said EMC's Rob Emsley, a senior director of product marketing at EMC.

The DLm8000's synchronous replication capability allows mainframe users faster recovery time objectives and more flexible recovery point objectives by eliminating any loss of data caused by a disaster or mainframe shutdown.

"This allows us to compete more effectively with IBM," Emsley continued. "Just as we've been delivering primary storage into that mainframe market ... what this disk library gives customers is more of a choice than just IBM tape or IBM virtual tape libraries."

The DLm8000 has a maximum throughput of 2.7GB/sec. That compares with the DLm6000, which offers up to 2GB/sec thoughput.

The new disk library connects directly to the mainframe through IBM's Fibre Connectivity (FICON) protocol. To the mainframe, the DLm8000 appears as a 3480, 3490 or 3590 IBM enterprise tape drive.

The DLm8000 supports up to 2,048 emulated tape drives, meaning a mainframe stores data in what it sees as up to 2,048 tape drive even though the data is being archived to spinning disk. "With physical tape drives (let's say 16) the user may have to delay the start of their daily processing because all of the drives are in use for a backup operation, or some other task. The customer can devote additional drives to the process, even temporarily," said Jim O'Connor, an EMC senior product marketing manager, in an email reply to questions from Computerworld. "With the high number of virtual drives this problem can be avoided."